log splitter project

[vince smith]

Hello All, I'm building a conical screw log splitter for tough Australian hardwoods.I'm still working on the gear reductions.I had the screw made at an engineering shop but it was not successfull, I believe this is because they used a live centre and could not get close enough to give me a small enough entry point.

I have a small chinese lathe and used a butchered $49.00 chain saw sharpener to cut the thread. This was very slow but I got there in the end.
I will try and post a short video.

Regards Vince

 

[vince smith]

Hello all, Sorry I didn't get the video to work so I'll try and post a photo,
unfortunatly its pretty ordinary.

regards Vince.

 

[VTsteader]

Looks sweet, Vince!

Is the idea behind it to turn that into a log until it splits?

-rob

 

[yomax4]

I just wonder if it's aggressive enough?

 

[vince smith]

Hello paul, Yes, thats it. There are some good examples on the net, one being hydrocut. I must say there are some really scary ones as well.

Hello youmax4, If you mean the depth of cut, I dont think that was the finished item. If you mean angle, thats 15 deg ( x 2 ) and I think I would try something closer to 10 deg. If I was to do another. I have a 10 hp honda
gas engine with pulleys 100 mm to 250 mm then chain reduction 17 th to 57 th and it still grinds to a screaming halt. I intend to put in another lay shaft with 2 more sprockets 17 th and 57 th. when time allows and I reckon that
should do it.

regards vince.

 

[jimmysisson]

Honda at 3600 rpm, x 2.5:1 belt = 1440 rpm, x 17/57 = 429. I think that's a bit faster than when I ran one on a truck axle at idle. Next stepdown, 429 x 17/57 = 128, your planned rpm unless I missed something. I think that's slower than you'll want it to run, and that would be lower if the Honda is turning slower. Sounds like you may need more power???
Jim

 

[J_J]

If you reduce the engine rpm down to say 600, which is a 6 : 1 ratio, the torque increases 6 times. 540 is the rpm of the tractor PTO conical log splitters, but then again, HP on a tractor is greater. Although you may start to screw the unit into a log/tree, at some point, resistance goes way up and the HP necessary to complete the split, goes way up.

If you get it half way in a really tough stump, and run out of HP, what are you going to do. Do you have a plan to back it out.

 

[vince smith]

Hello fellas,
Jim, You haven't missed anything. I figured I'd rather it be a bit slow and have plenty of grunt and also something I'm not scared to use.

J.J. In trials with the higher gearing I did get some stuck fast but was able to
wind it out by hand.

My choice of gearing was from stuff I mostly had. The motor cost me $125.00

Regards Vince.

 

[jimmysisson]

I recall the most power required was just as the lead started to split the bolt. Kind of the same with a piston-wedge splitter. Once the split starts, the power requirement goes down. That doesn't mean you can't get stuck in a gnarly piece most of the way in though! I wonder if a big flywheel would get you past the hard early push?
Jim

 

[vince smith]

Hello Jim, strangely enough a heavy machine mechanic (friend) also suggested I considered a flywheel. I will try everything else first because when/if I hit the kill switch I want to be confident it stops quickly.

I'm still fairly confident It will work because the "thread" is about 8 threads per inch. and this in itself is a form of gearing, so it should make the 10 hp more workable.( he hopes) I work it out at 30 sec + for a 12" log as I expect not to have bore in much more than half way.

I cannot get to it yet as we are still cutting and collecting trees courtesy of cyclone yasi.

regards vince.

 

[jimmysisson]

Maybe you're ok with a 30-second split time but I'd get annoyed waiting. My big 5" cyl. splitter takes 24 sec to cycle and I wish it were faster.
I wonder if there's a way to use a flywheel with a dog clutch between the flywheel and the screw. It's true you want to be able to disable the rotation quickly. The dog clutch wouldn't be used much, just when needed, and could be a simple thing I think. I just googled dog clutch and got nowhere though...
Jim

 

[easygo]

I have no suggestions but can give you a few numbers. I use one of those cone-shaped screw splitters on the PTO of my tractor. If I wanted 540 PTO speed I would have to run the engine at 2600rpm. That would be way too fast though. I run the engine at 1500rpm and that splits wood fast enough so I only have to wait 1-8 seconds per split depending on wood species and thickness. The cone only has 3 "threads" per inch so it pulls the wood on rather fast. Since you are working with 8 threads per inch your power does not need to be as high as it will drive itself less into the wood per revolution. Good luck with the project and post pictures.

 

[vince smith]

Hello Folk, Its time for me to fess up. My cone was no better than the engineering shops. The extra reduction is spot on though.
My "tooth" profile was a bit like corrogated iron, not sharp enough, or deep enough I suspect. I deepened it with an angle grinder and tried to use a tapered file to sharpen it but still not good.

It will go in aways but then just churns out fine sawdust, then starts smoking.

I'm considering buying a cone from U.K or U.S.A. (with replacable tips) but cannot get through to those I've tried so if anyone can get me a contact I would appreciate it.
Regards Vince Smith.